converter_test.cpp

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                           c_neg_overflow,
                           c_converted,
                           c_converted,
                           c_converted,
                           c_converted
                          ) ;

  test_rounding_conversion(SET_FNTPL_ARG(T),
                           SET_FNTPL_ARG(boost::numeric::Trunc<S>),
                           max,
                           c_converted,
                           c_converted,
                           c_converted,
                           c_converted,
                           c_pos_overflow
                          ) ;

  cout << "Testing 'RoundEven' Float2IntRounder policy\n";

  test_rounding_conversion(SET_FNTPL_ARG(T),
                           SET_FNTPL_ARG(boost::numeric::RoundEven<S>),
                           min,
                           c_neg_overflow,
                           c_converted,
                           c_converted,
                           c_converted,
                           c_converted
                          ) ;

  test_rounding_conversion(SET_FNTPL_ARG(T),
                           SET_FNTPL_ARG(boost::numeric::RoundEven<S>),
                           max,
                           c_converted,
                           c_converted,
                           c_converted,
                           c_pos_overflow,
                           c_pos_overflow
                          ) ;

  cout << "Testing 'Ceil' Float2IntRounder policy\n";

  test_rounding_conversion(SET_FNTPL_ARG(T),
                           SET_FNTPL_ARG(boost::numeric::Ceil<S>),
                           min,
                           c_neg_overflow,
                           c_converted,
                           c_converted,
                           c_converted,
                           c_converted
                          ) ;

  test_rounding_conversion(SET_FNTPL_ARG(T),
                           SET_FNTPL_ARG(boost::numeric::Ceil<S>),
                           max,
                           c_converted,
                           c_converted,
                           c_converted,
                           c_pos_overflow,
                           c_pos_overflow
                          ) ;

  cout << "Testing 'Floor' Float2IntRounder policy\n" ;

  test_rounding_conversion(SET_FNTPL_ARG(T),
                           SET_FNTPL_ARG(boost::numeric::Floor<S>),
                           min,
                           c_neg_overflow,
                           c_neg_overflow,
                           c_converted,
                           c_converted,
                           c_converted
                          ) ;

  test_rounding_conversion(SET_FNTPL_ARG(T),
                           SET_FNTPL_ARG(boost::numeric::Floor<S>),
                           max,
                           c_converted,
                           c_converted,
                           c_converted,
                           c_converted,
                           c_pos_overflow
                          ) ;

}

void test_round_even( double n, double x )
{
  double r = boost::numeric::RoundEven<double>::nearbyint(n);
  BOOST_CHECK( r == x ) ;
}

void test_round_even()
{
  cout << "Testing 'RoundEven' tie-breaking\n";

  double min = boost::numeric::bounds<double>::lowest();
  double max = boost::numeric::bounds<double>::highest();

#if !defined(BOOST_NO_STDC_NAMESPACE)
  using std::floor ;
  using std::ceil ;
#endif
  test_round_even(min, floor(min));
  test_round_even(max, ceil (max));
  test_round_even(2.0, 2.0);
  test_round_even(2.3, 2.0);
  test_round_even(2.5, 2.0);
  test_round_even(2.7, 3.0);
  test_round_even(3.0, 3.0);
  test_round_even(3.3, 3.0);
  test_round_even(3.5, 4.0);
  test_round_even(3.7, 4.0);
}

int double_to_int ( double n ) { return static_cast<int>(n) ; }

void test_converter_as_function_object()
{
  cout << "Testing converter as function object.\n";

  // Create a sample sequence of double values.
  std::vector<double> S ;
  for ( int i = 0 ; i < 10 ; ++ i )
    S.push_back( i * ( 18.0 / 19.0 ) );

  // Create a sequence of int values from 's' using the standard conversion.
  std::vector<int> W ;
  std::transform(S.begin(),S.end(),std::back_inserter(W),double_to_int);

  // Create a sequence of int values from s using a default numeric::converter
  std::vector<int> I ;
  std::transform(S.begin(),
                 S.end(),
                 std::back_inserter(I),
                 boost::numeric::converter<int,double>()
                ) ;

  // Match 'w' and 'i' which should be equal.
  bool double_to_int_OK = std::equal(W.begin(),W.end(),I.begin()) ;
  BOOST_CHECK_MESSAGE(double_to_int_OK, "converter (int,double) as function object");

  // Create a sequence of double values from s using a default numeric::converter (which should be the trivial conv).
  std::vector<double> D ;
  std::transform(S.begin(),
                 S.end(),
                 std::back_inserter(D),
                 boost::numeric::converter<double,double>()
                ) ;

  // Match 's' and 'd' which should be equal.
  bool double_to_double_OK = std::equal(S.begin(),S.end(),D.begin()) ;
  BOOST_CHECK_MESSAGE(double_to_double_OK, "converter (double,double) as function object");
}

#if BOOST_WORKAROUND(__IBMCPP__, <= 600 ) // VCAPP6
#  define UNOPTIMIZED
#else
#  define UNOPTIMIZED volatile
#endif

void test_optimizations()
{
  using namespace boost;
  using namespace numeric;

  float fv0 = 18.0f / 19.0f ;

  // This code deosn't produce any output.
  // It is intended to show the optimization of numeric::converter<> by manual inspection
  // of the generated code.
  // Each test shows first the equivalent hand-coded version.
  // The numeric_cast<> code should be the same if full compiler optimization/inlining is used.

  //---------------------------------
  // trivial conversion.
  //
    // equivalent code:
      UNOPTIMIZED float fv1a = fv0 ;

    float fv1b = numeric_cast<float>(fv0);
    unused_variable(fv1a);
    unused_variable(fv1b);
  //
  //---------------------------------

  //---------------------------------
  // nonsubranged conversion.
  //
    // equivalent code:
      UNOPTIMIZED double dv1a = static_cast<double>(fv0);

    double dv1b = numeric_cast<double>(fv0);
    unused_variable(dv1a);
    unused_variable(dv1b);
  //
  //---------------------------------

  //------------------------------------------------------
  // subranged conversion with both-sided range checking.
  //

    // equivalent code:

      {
        double const& s = dv1b ;
        // range checking
        range_check_result r =  s < static_cast<double>(bounds<float>::lowest())
                                  ? cNegOverflow : cInRange ;
        if ( r == cInRange )
        {
          r = s > static_cast<double>(bounds<float>::highest()) ? cPosOverflow : cInRange ;
        }
        if ( r == cNegOverflow )
          throw negative_overflow() ;
        else if ( r == cPosOverflow )
               throw positive_overflow() ;
        // conversion
        UNOPTIMIZED float fv2a = static_cast<float>(s);
        unused_variable(fv2a);
      }

    float fv2b = numeric_cast<float>(dv1b);
    unused_variable(fv2b);
  //
  //---------------------------------


  //---------------------------------
  // subranged rounding conversion
  //
    // equivalent code:

      {
        double const& s = dv1b ;
        // range checking
        range_check_result r = s <= static_cast<double>(bounds<int>::lowest()) - static_cast<double>(1.0)
                                 ? cNegOverflow : cInRange ;
        if ( r == cInRange )
        {
          r = s >= static_cast<double>(bounds<int>::highest()) + static_cast<double>(1.0)
                ? cPosOverflow : cInRange ;
        }
        if ( r == cNegOverflow )
          throw negative_overflow() ;
        else if ( r == cPosOverflow )
               throw positive_overflow() ;
        // rounding

#if !defined(BOOST_NO_STDC_NAMESPACE)
        using std::floor ;
#endif

        double s1 = floor(dv1b + 0.5);

        // conversion
        UNOPTIMIZED int iv1a = static_cast<int>(s1);
        unused_variable(iv1a);
      }

    int iv1b = numeric_cast<int>(dv1b);
    unused_variable(iv1b);
  //
  //---------------------------------
}

int test_main( int, char* argv[] )
{
  std::cout << std::setprecision( std::numeric_limits<long double>::digits10 ) ;

  test_conversions();
  test_overflow_handlers( SET_FNTPL_ARG(boost::int16_t), SET_FNTPL_ARG(boost::int32_t));
  test_round_style(SET_FNTPL_ARG(boost::int32_t), SET_FNTPL_ARG(double) ) ;
  test_round_even() ;
  test_converter_as_function_object();
  test_optimizations() ;

  return 0;
}
//---------------------------------------------------------------------------